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Biomedical subjects

D C Hall

Publications and source records attributed to D C Hall.

11 recordsLinked to original sources
PubMed1991

Effect on neutrophil kinetics and serum opsonic capacity of intravenous administration of immune globulin to neonates with clinical signs of early-onset sepsis.

This study was designed to test the hypothesis that administration of immune globulin to human neonates with early-onset bacterial sepsis would (1) facilitate neutrophil egress from the marrow, (2) improve serum opsonic capacity, and (3) facilitate recovery from the infectious illness. Twenty-two newborn infants with clinical signs of early-onset sepsis were given an intravenous infusion of either 750 mg of immune globulin (IVIG) per kilogram of body weight or the same volume of a vehicle control (albumin). All 22 infants survived, but significant hematologic, immunologic, and respiratory differences were observed after the IVIG and not after the control infusion. Eleven of the patients had neutropenia; 24 hours after the infusions, the neutropenia had resolved in all six IVIG recipients but persisted in all five control recipients (p less than 0.001). Ten patients had I/T neutrophil ratios (a measure of immature neutrophils to total neutrophils on the leukocyte differential count) of less than 0.2. One hour after completion of the infusions, all five IVIG recipients had elevated I/T ratios (mean +/- SEM:0.10 +/- 0.05 before vs 0.43 +/- 0.03 after infusion; p less than 0.001), suggesting a prompt release of neutrophils from the marrow neutrophil storage pool into the circulation; no increase in the I/T ratio was observed in the control recipients. Six hours after the IVIG infusions, the ratio of arterial oxygen tension to fraction of inspired oxygen increased; no increase was observed after control infusions. Serum concentrations of IgG, IgG1, IgG2, IgG3, IgG4, and total hemolytic complement and the capacity of serum to support opsonophagocytosis of type II and type III group B streptococci increased markedly in the IVIG recipients but not in the control subjects. We conclude that administration of 750 mg IVIG per kilogram to neonates with clinical signs of early-onset sepsis was associated with immunologic, hematologic, and physiologic improvement.

Bacterial Infections↗
PubMed1979

Effects of certain training parameters on detection of simulated breast cancer.

Forty-two female subjects, constituting 14 groups, palpated a silicone breast model in a lump detection task. Three variables, number of trials (amount of practice), search pattern requirement (restricted vs. unrestricted), and the presence or absence of lumps, were manipulated according to 3 x 2 x 2 design. The effect of all modes of practice on detection performance in posttest 1 was evidenced by an increase in percent of lumps detected and a decrease in detection threshold, but no form of practice was superior to the others. Following posttest 1 a brief search-training procedure was administered to 39 subjects which further lowered detection threshold, increased percent of lumps detected, and increased trial duration in posttest 2. The results indicate the effectiveness of the training procedure for improving detection ability and suggest the need for a more complex model to determine more specifically the effects of the practice models employed.

Adolescent↗
PubMed1977

Progress in manual breast examination.

Manual breast examination, despite recent advances in mechanical screening devices, remains a primary diagnostic procedure for early detection of breast cancer. The potential effectiveness of breast self-examination for reducing mortality relies on the effectiveness of a technology for training women to detect small tumors through manual palpation. Research indicates that although the regular practice of breast self-examination can lead to the detection of small tumors, current training methods are inadequate to ensure proper performance and maintain regular practice. An alternative interdisciplinary research and training approach, involving medicine, biomaterials engineering, psychophysics, and experimental psychology, is suggested. A dynamic lifelike breast model with variable lumps would provide the basis for generating systematic data regarding the factors affecting detection of small lumps and lead to development and evaluation of efficient and effective methods to teach manual examination.

Breast↗